1. Field of the Invention
The present invention relates to a semiconductor device including semiconductor chips and members that draw out electrical leads from the semiconductor chips, a semiconductor package member used for such a semiconductor device, and a manufacturing method of such a semiconductor device, and more particularly, to the semiconductor device, the semiconductor package member, and the semiconductor device manufacturing method that are suitable for a high-frequency (high-speed) circuit.
2. Description of the Related Art
In recent years, there has been a demand for a higher-frequency, higher-speed operation in a band of several GHz or higher in electronic equipment, communication equipment, and so on. In order to guarantee the operation performance of semiconductor devices used in electronic equipment and communication equipment in such a frequency band, it is naturally necessary to ensure the high-frequency, high-speed operability of semiconductor chips themselves, but it is also necessary to improve passive parts which are connected to the semiconductor chips for use and to improve a connecting method thereof.
First, a semiconductor device having bypass capacitors mounted/connected therein as passive parts will be explained as an example. FIG. 21A and FIG. 21B are views showing a structure example of such a semiconductor device in a prior art. FIG. 21A is a side view thereof and FIG. 21B is a top view thereof. As shown in FIG. 21A and FIG. 21B, this semiconductor device is so structured that a semiconductor chip 302 is flipchip-mounted on a wiring board 301. Projected electrodes (bumps) 303 made of, for example, gold are formed on pads (not shown) of the semiconductor chip 302 in advance for use in the flipchip mounting. The projected electrodes 303 are bonded to mounting lands provided on the wiring board 301 by, for example, a bonding technique.
The reference numeral 304 denotes a sealing resin to shield and protect the bonded portions and so on from the atmosphere, and the reference numeral 306 denotes solder balls for use in mounting this semiconductor device on another wiring board or the like. The solder balls 306 are electrically connected to the projected electrodes 303 of the semiconductor chip 302 by wirings (not shown) provided on the wiring board 301 and wirings (not shown) passing therethrough. The reference numeral 305 denotes bypass capacitors mounted on the wiring board 301 (detailed later).
Another structure example of a conventional wiring board having inductors (surface-mounted inductors) connected/mounted thereon as passive parts is shown in FIG. 22. As shown in FIG. 22, a surface-mounted semiconductor device 312 (package product) and surface mounted inductors 314 are mounted adjacent to each other on a wiring board 311 in this example. They are mounted by, for example, the reflow of solder. The semiconductor device 312 and the inductors 314 are electrically connected to each other by wirings 313 on the wiring board 311.
Especially when the semiconductor chip 302 in the semiconductor device shown in FIG. 21A and FIG. 21B is a logic integrated circuit or a memory, a transient electric current flows through power supply lines (not shown) due to input/output or internal switching. Especially when the switching operations are performed synchronously in a large number of the input/output lines or when a high-speed (high-frequency) operation is performed, the energy of the transient electric current becomes considerably large. The occurrence of a transient electric current generally causes the occurrence of fluctuation in a supplied voltage near the semiconductor chip 302 due to the impedance that the patterns of the power supply lines and the ground (not shown) have, which further causes an adverse effect of the malfunction of the semiconductor chip 302 itself.
Therefore, in order to eliminate such an adverse effect, bypass capacitors 305 are provided between the power supply lines and the grounds near the semiconductor chip 302, as shown in FIG. 21A and FIG. 21B, to prevent the electric current fluctuation at the upstream-side power supply lines which are supply sources of the transient electric current and at the grounds.
It is more preferable that the bypass capacitors 305 are disposed nearer to power supply terminals (pads) and ground terminals (pads) of the semiconductor chip 302 as is apparent from the abovementioned reason for preventing the voltage fluctuation (to further comment, this arrangement is even more preferable since wiring patterns and so on in a high-frequency, high-speed circuit are not simple leads but have impedance), but the arrangement thereof seldom comes near to such ideal state in actual practice due to the limited mounting space. For example, in the case shown in FIG. 21A and FIG. 21B, the bypass capacitors 305 are of a surface-mounted type and are disposed on a semiconductor device side of the wiring board 301, but they are arranged on corners (four corners) thereof.
One reason for such arrangement is that, though the arrangement pitch of input/output portions (pads) of the semiconductor chip 302 can be, for example, about 80 μm and wiring patterns on the wiring board 301 are accordingly formed, the interval between both terminals of the bypass capacitor 305 is 1 mm order at smallest and therefore, a mounting space which is accordingly large is required for forming wiring patterns for the bypass capacitor 305.
Therefore, minimizing the impedance of the power supply lines and the grounds is practically only way to prevent the occurrence of the aforesaid adverse effect when the mounting positions of the bypass capacitors 305 are thus limited. An adoptable method of reducing the impedance of the power supply lines and the grounds is, for example, such that the power supply terminals (pads) and the ground terminals (pads) of the semiconductor chip 302 are both provided in large numbers, and the wiring patterns are formed on the wiring board 301 so as to correspond to a large number of the power supply terminals and the ground terminals.
This method is disadvantageous in that the semiconductor chip 302 becomes large in size since a large number of the terminals are provided therein, and that it becomes necessary to further narrow the pitch of the pads and to further narrow the pitch of the connection with the wiring board 301 since a larger number of the terminals are provided in the same area. Therefore, there is a limit to the use of the semiconductor device as shown in FIG. 21A and FIG. 21B for the higher-frequency and higher-speed operation.
Further, the following can be said with respect to the board mounting structure shown in FIG. 22, which is used, for example, for a high-frequency VCO (voltage controlled oscillator) circuit. Incidentally, it is assumed here that the semiconductor device 312, which is constituted of an integrated chip of, for example, an NMOS type, is so structured that a pair of MOS transistors are feedback-connected therein to constitute an astable multivibrator, and electric currents between sources and drains of the MOS transistors are supplied from the outside via the inductors 314.
When the use of thus structured VCO is attempted in a high-frequency band of a GHz order, the involvement of parasitic elements is prominent in the wiring patterns 313 and the inductors 314, which influences the quality of oscillation output (level of phase modulation noise). This is because, for example, electromagnetic coupling or induction is caused by the parasitic elements. Therefore, there is also a limit to the use of the board mounting structure as shown in FIG. 22 for the higher-frequency, higher-speed operation.
As discussed above, under the present situation, the use of a semiconductor device mounted together with passive parts has a problem when the higher frequency operation is to be realized. The present invention is made in consideration of the above circumstances, and the object thereof is to provide a semiconductor device having semiconductor chips and members to draw out electrical leads from the semiconductor chips, a semiconductor package member used in such a semiconductor device, and a manufacturing method of such a semiconductor device that are usable at a higher frequency and a higher speed.